Carbon and its Compounds · Class 10 Science: 216 MCQs with answers

Q1. Carbon's electronic configuration is:

Q2. Why does carbon form compounds mainly by covalent bonding?

Q3. Why do covalent compounds generally have low melting and boiling points and not conduct electricity?

Q4. State the two characteristic features of carbon that give rise to a very large number of compounds.

Q5. Diamond and graphite are both carbon, yet one cuts glass and the other marks paper. Explain.

Q6. Why does graphite conduct electricity while diamond does not?

Q7. What are fullerenes? Describe C-60.

Q8. Write the general formulas of alkanes, alkenes and alkynes, with the first two members of each.

Q9. What are saturated and unsaturated hydrocarbons? Which are more reactive?

Q10. What is a homologous series? State its three main characteristics.

Q11. Give the IUPAC names of: (a) C₃H₈, (b) C₂H₄, (c) C₂H₂, (d) C₂H₅OH, (e) CH₃COOH.

Q12. Why do saturated and unsaturated hydrocarbons burn with different flames?

Q13. Why does the bottom of cooking vessels blacken when the gas stove's air holes are blocked?

Q14. How would you convert ethanol into ethanoic acid? Name the reagent and the reaction type.

Q15. What is hydrogenation? Write its equation form and industrial application.

Q16. Why is the reaction between methane and chlorine called a substitution reaction, and why does it need sunlight?

Q17. Why are oils healthier than hydrogenated fats for cooking?

Q18. Which statement correctly describes buckminsterfullerene?

Q19. Melting wax does NOT break C-C or C-H bonds because melting overcomes only:

Q20. Which solution conducts electricity?

Q21. The strength of C-C bonds owes chiefly to carbon's:

Q22. Silicon's chains are short and reactive because Si-Si bonds are:

Q23. Graphite is used as a lubricant because its:

Q24. Diamond does NOT conduct because:

Q25. Which molecule contains a double bond?

Q26. The shapes carbon chains can take are:

Q27. Which pair of properties belongs to covalent compounds?

Q28. Carbon's versatility does NOT include:

Q29. Draw (describe) the electron-dot structures of (a) H₂O and (b) N₂.

Q30. What would be the electron-dot structure of carbon dioxide (CO₂)?

Q31. Why are carbon-carbon bonds strong, and why can't silicon match them?

Q32. A compound X melts at 42 °C, is insoluble in water but dissolves in kerosene, and its molten form does not conduct. What type of compound is X? Give three reasons.

Q33. Which formula represents an alkyne?

Q34. Which is unsaturated?

Q35. In a homologous series, as chain length increases the boiling point:

Q36. Members of a homologous series share:

Q37. The compound CH₃CHO contains the ______ group.

Q38. Chloromethane is written:

Q39. The mass difference between propanol and butanol is:

Q40. Define structural isomerism. Draw (describe) the two isomers of butane.

Q41. Why do the physical properties change but chemical properties stay similar along a homologous series?

Q42. Identify the functional group and name the family: (a) CH₃OH, (b) CH₃CHO, (c) CH₃COCH₃, (d) HCOOH.

Q43. Why are alkenes and alkynes said to begin at the second member conceptually (n = 2)?

Q44. Write the next TWO homologues of ethanol, with formulas.

Q45. Burning coal and petroleum release the gases that cause acid rain. Those gases are the oxides of:

Q46. Which will undergo an ADDITION reaction?

Q47. Which will undergo SUBSTITUTION with chlorine in sunlight?

Q48. The reaction type of CH₄ + 2O₂ → CO₂ + 2H₂O among the four is:

Q49. The gas evolved alongside CH₃Cl in methane's substitution is:

Q50. Which requires a CATALYST?

Q51. Which requires LIGHT?

Q52. The overall lesson of this topic is that a carbon compound's reactions are decided by its:

Q53. Alkaline KMnO₄ is added drop by drop to warm ethanol. Why does its colour first disappear and later persist?

Q54. Distinguish between addition and substitution reactions with one example each.

Q55. Give one reason each why (a) carbon compounds are used as fuels, (b) fossil-fuel burning causes acid rain.

Q56. The gas from ethanol + sodium burns with a:

Q57. The ester's smell is detected by:

Q58. Equal concentrations of HCl and ethanoic acid — the ethanoic acid solution has:

Q59. Sodium ethanoate is formed when ethanoic acid reacts with:

Q60. Soap fails to lather well in:

Q61. Which is fully biodegradable?

Q62. Shampoos and washing powders are usually:

Q63. The reaction CH₃COOH + NaOH → CH₃COONa + H₂O is a:

Q64. Micelle formation requires the medium to be:

Q65. Carbon has four electrons in its outer shell. Which statement explains why it shares them rather than losing or gaining four?

Q66. Consider these statements about the covalent bond. I. It is formed by the sharing of a pair of electrons between two atoms. II. Both atoms count the shared pair towards their own octet. III. Hydrogen is satisfied by a duet rather than an octet. IV. The shared electrons belong to one atom only. Which statements are correct?

Q67. Assertion (A): Carbon forms four bonds in every one of its compounds. Reason (R): Carbon has four outer electrons and needs four more to complete its octet, so it shares each of them with another atom.

Q68. Nitrogen has five outer electrons and two nitrogen atoms join to form N₂. The bond between them is:

Q69. Assertion (A): Oxygen is written O=O and nitrogen N≡N. Reason (R): Oxygen has five outer electrons and nitrogen six, so they share three pairs and two pairs respectively.

Q70. Which is the correct explanation of why candle wax melts in the warmth of a hand while sodium chloride needs over a thousand degrees?

Q71. Why do covalent compounds generally fail to conduct electricity?

Q72. Consider these statements about carbon's versatility. I. Catenation is carbon's ability to bond to other carbon atoms in chains and rings. II. Tetravalency means each carbon makes four bonds. III. Together these two allow millions of different carbon compounds. IV. Silicon catenates just as strongly as carbon does. Which statements are correct?

Q73. Which statement best explains why carbon forms more compounds than all the other elements together?

Q74. Diamond and graphite are both pure carbon, yet diamond is the hardest natural substance and graphite is soft and slippery. The difference arises because:

Q75. Two pencil lines drawn thickly on paper will carry enough current to light a small bulb. This works because pencil lead is:

Q76. Assertion (A): Diamond has an extremely high melting point although it is a covalent substance. Reason (R): There are no separate molecules in diamond — the whole crystal is one network of strong covalent bonds that must be broken to melt it.

Q77. Which statement explains why graphite is used both as a lubricant and as an electrode?

Q78. Consider these statements about multiple bonds. I. A single bond is one shared pair of electrons. II. A double bond is two shared pairs, that is four electrons. III. A triple bond is three shared pairs, that is six electrons. IV. A triple bond is weaker than a single bond. Which statements are correct?

Q79. In the molecule O=C=O, the total number of shared electron PAIRS in the whole molecule is:

Q80. Consider these statements about the water molecule. I. The oxygen atom shares one pair of electrons with each hydrogen atom. II. The oxygen atom keeps two pairs to itself as lone pairs. III. Each hydrogen atom is satisfied with a duet. IV. Water is an ionic compound because it contains oxygen. Which statements are correct?

Q81. Which of these best explains why most carbon compounds dissolve in kerosene or petrol rather than in water?

Q82. Which of these is NOT a reason for carbon's enormous number of compounds?

Q83. Assertion: Covalent compounds have low melting points. Reason: The covalent bonds within their molecules are very weak.

Q84. Assertion: Diamond and graphite have different properties. Reason: They differ in the arrangement and bonding of the same carbon atoms.

Q85. The electron-dot structure of CO₂ (O=C=O) contains:

Q86. In H₂S, sulphur (2,8,6) forms:

Q87. Which achieves a DUET rather than an octet in covalent molecules?

Q88. Case: A white solid melts at 63 °C, doesn't conduct even molten, dissolves in kerosene. It is likely:

Q89. Case: Two pencils' 'leads' short-circuit a paper circuit when drawn thickly. The conductor is:

Q90. Melting point order expected: diamond vs candle wax vs NaCl:

Q91. Why is diamond's melting point extremely HIGH though it is covalent?

Q92. The molecule with exactly two lone pairs on its central atom:

Q93. Explain fully why carbon always bonds covalently, illustrate with the electron-dot formation of methane, and derive the general property profile of covalent compounds from the nature of the bond.

Q94. 'Catenation and tetravalency together make carbon the element of life and industry.' Explain both properties, why carbon performs them uniquely well, and support the claim with examples spanning fuels, materials and biology.

Q95. Compare diamond and graphite under structure, hardness, conduction, appearance and uses; explain how identical atoms produce opposite properties; and add fullerenes to complete carbon's allotrope family.

Q96. Design a three-test bench investigation to decide whether an unknown solid is ionic or covalent, predict both outcome patterns, and apply it: substance A melts at 78 °C, dissolves in petrol, never conducts; substance B melts above 700 °C, dissolves in water, conducts only when molten or dissolved.

Q97. Consider these statements about hydrocarbons. I. They contain only carbon and hydrogen. II. Alkanes have only single bonds and are saturated. III. Alkenes and alkynes are unsaturated. IV. Ethanol is a hydrocarbon because it contains carbon and hydrogen. Which statements are correct?

Q98. A hydrocarbon has five carbon atoms and only single bonds. Its molecular formula is:

Q99. What is the best explanation of why the alkane series begins at one carbon but the alkene series begins at two?

Q100. A hydrocarbon has the formula C₅H₈. It belongs to the family of:

Q101. Which statement correctly describes the natural gas and cooking gas we use?

Q102. Assertion (A): Ethene and ethyne are both called unsaturated hydrocarbons. Reason (R): Each of them has fewer hydrogen atoms than the alkane of the same carbon number, because a multiple bond has taken the place of hydrogens.

Q103. Ethyne is burnt with oxygen in a welding torch rather than with air. The reason is:

Q104. Which statement best explains the word SATURATED as used for hydrocarbons?

Q105. Butane, C₄H₁₀, exists in two forms — one a straight chain of four carbons and the other a three-carbon chain with a branch. These two are:

Q106. Consider these statements about a homologous series. I. Successive members differ by a CH₂ group. II. All members share the same general formula. III. All members have similar chemical properties. IV. All members have the same boiling point. Which statements are correct?

Q107. Which is the correct explanation of why a functional group matters more than chain length in deciding how a compound behaves?

Q108. Four functional groups and four families are listed. Which pairing is WRONG?

Q109. A compound has a chain of four carbon atoms ending in a —COOH group. Its IUPAC name is:

Q110. Which statement best explains how an IUPAC name is built up?

Q111. The compound CH₃COCH₃ has a —CO— group between two carbon groups. Its family and IUPAC ending are:

Q112. Which of these hydrocarbons has NO structural isomer?

Q113. Which pair of compounds are HOMOLOGUES of each other?

Q114. Assertion (A): The boiling points of alkanes rise steadily from methane to butane to octane. Reason (R): The longer the molecule, the weaker the forces between neighbouring molecules, so less energy separates them.

Q115. The next member after C₄H₁₀ in its series, and the next after C₂H₄ in its series, are respectively:

Q116. Consider these statements about naming a carbon compound by the IUPAC system. I. The root names the longest carbon chain. II. The suffix names the functional group. III. When the suffix begins with a vowel, the final 'e' of the root is dropped. IV. The name depends on who discovered the compound. Which statements are correct?

Q117. Which molecular formula CANNOT belong to any alkane, alkene or alkyne?

Q118. Petroleum is separated into petrol, kerosene and diesel by distillation rather than by any chemical reaction. This is possible because:

Q119. The number of covalent bonds in ethane (C₂H₆) is:

Q120. The number of C-H bonds in propane is:

Q121. Consider these statements about isomers and homologues. I. Isomers share a molecular formula but differ in structure. II. Homologues share a functional group but differ by CH₂ steps. III. Isomers have the same molecular mass as each other. IV. Homologues have the same molecular mass as each other. Which statements are correct?

Q122. Which pair are isomers?

Q123. Assertion: Propane has no isomers. Reason: With three carbons only one chain arrangement is possible.

Q124. Assertion: All members of the alcohol family show similar reactions. Reason: They all carry the −OH functional group.

Q125. A compound has 5 carbons, all single bonds, and an −OH on the end. Its IUPAC name is:

Q126. Assertion (A): Methanol and ethanol undergo entirely different chemical reactions, one being poisonous and the other not. Reason (R): They belong to the same homologous series and carry the same —OH functional group.

Q127. Which statement best explains why an unsaturated hydrocarbon is chemically more reactive than a saturated one?

Q128. Case: A gas cutting through steel in a workshop burns with an extremely hot flame. The gas is likely:

Q129. Which of these best explains why a homologous series is such a useful idea?

Q130. A compound has the molecular formula C₃H₆O and contains a −CHO group. Name it and its family.

Q131. Explain the concept of a homologous series using the alkane family: list the first five members with formulas and states, demonstrate the CH₂/14 u rule, show the gradual physical trend, and explain why the series concept makes organic chemistry learnable.

Q132. Explain structural isomerism in detail: definition, why it becomes possible only from butane onward, the two C₄H₁₀ isomers with a property difference, the three isomers of pentane, and why isomer counts explode with chain length.

Q133. Build a complete guide to naming the carbon compounds of this chapter: the root system, the bond suffixes, the functional-group suffixes/prefixes with one example each, and then name and justify: CH₃CH₂CH₂OH, CH₃COCH₃, HCOOH, C₄H₈ (one double bond), CH₃Cl.

Q134. 'The functional group is the driver; the carbon chain is just the vehicle.' Explain what functional groups are and justify this statement by comparing (a) ethane vs ethanol vs ethanoic acid — three compounds on the same two-carbon chassis — and (b) the entire alcohol family behaving alike.

Q135. Consider these statements about the combustion of carbon compounds. I. Complete combustion gives carbon dioxide and water. II. Heat and light are released. III. Incomplete combustion leaves unburnt carbon as soot. IV. Combustion of a carbon compound gives the free element carbon as its main product. Which statements are correct?

Q136. What is the best explanation of why a saturated hydrocarbon burns with a clean blue flame while an unsaturated one burns with a sooty yellow flame?

Q137. A gas stove burning LPG, a saturated fuel, suddenly gives a yellow flame and blackens the vessel. The most likely cause is:

Q138. Assertion (A): The conversion of ethanol to ethanoic acid is called an oxidation. Reason (R): Ethanoic acid is the main constituent of vinegar.

Q139. Alkaline potassium permanganate is added drop by drop to warm ethanol. The purple colour disappears at first, then a drop makes it stay. The persistence shows that:

Q140. Which statement best explains what a catalyst such as nickel does in the hydrogenation of vegetable oil?

Q141. Consider these statements about the hydrogenation of vegetable oils. I. Hydrogen adds across the carbon-to-carbon double bonds. II. The liquid oil becomes a solid fat. III. The product is saturated where the oil was unsaturated. IV. The product is healthier than the original oil. Which statements are correct?

Q142. Which statement correctly matches a reaction type to the kind of compound that shows it?

Q143. Methane is mixed with chlorine and the mixture is kept in the dark; nothing happens. Brought into sunlight, it reacts at once. This shows that:

Q144. Methane is treated with an EXCESS of chlorine in sunlight. The substitution continues until the final product is:

Q145. Which is the correct explanation of why the substitution of methane by chlorine produces a MIXTURE rather than a single product?

Q146. Which statement best explains why unsaturated vegetable oils are recommended over saturated fats for cooking?

Q147. Which of these best explains why ethanol burning in a spirit lamp leaves no soot on the vessel above it?

Q148. Bromine water is shaken with two colourless liquids. With the first the orange colour disappears; with the second it stays. The two liquids are respectively:

Q149. What is the best explanation of why an oxidising agent is needed to turn ethanol into ethanoic acid, when burning ethanol also adds oxygen to it?

Q150. Ethene is passed with hydrogen over hot nickel. Which statement describes the product and the reaction type?

Q151. Consider these statements about the four reaction types of carbon compounds. I. Combustion needs oxygen and releases heat and light. II. Addition needs a catalyst such as nickel. III. Substitution by chlorine needs sunlight. IV. Oxidation of an alcohol needs an oxidising agent. Which statements are correct?

Q152. Which is the correct explanation of why the flame test and the bromine-water test together give a firmer answer than either alone?

Q153. Ethane's combustion equation is:

Q154. Consider these statements about incomplete combustion. I. It happens when the supply of oxygen is insufficient. II. It deposits soot, which is unburnt carbon. III. It releases less energy than complete combustion of the same fuel. IV. It can also produce carbon monoxide, which is poisonous. Which statements are correct?

Q155. Welding torches burn ethyne in pure OXYGEN because:

Q156. Which statement best explains why addition is preferred to substitution when a chemist wants one pure product?

Q157. Assertion: Vanaspati is solid while vegetable oil is liquid. Reason: Hydrogenation saturates the oil's double bonds, letting chains pack closely.

Q158. Assertion: The nickel in hydrogenation can be reused. Reason: A catalyst is not consumed in the reaction.

Q159. Case: Two gas jars burn samples — jar A's flame is blue, jar B's is smoky yellow. In excess air, the fuels could be:

Q160. Case: A food factory wants to harden its oil for spreads. The full requirement list is:

Q161. In C₂H₅OH → CH₃COOH, the ethanol has been:

Q162. Bromine water stays ORANGE when shaken with:

Q163. The flame test and bromine-water test together can distinguish:

Q164. Which change is chemically an OXIDATION?

Q165. Hydrogenation is chemically a:

Q166. Assertion (A): Coal and petroleum are burnt in enormous quantities and their combustion is a major cause of acid rain. Reason (R): These fuels contain sulphur and nitrogen compounds whose oxides dissolve in rainwater to form acids.

Q167. A hydrocarbon decolourises bromine water and burns with a sooty flame. What can you conclude? Which single reagent test would a saturated hydrocarbon fail to show?

Q168. Describe combustion of carbon compounds comprehensively: the general reaction, two balanced examples, the flame rules with their reasons, the stove-diagnosis application, and the environmental cost of fossil-fuel combustion.

Q169. Describe the oxidation of ethanol to ethanoic acid as a complete experiment: apparatus, procedure, the drop-wise KMnO₄ observation and its explanation, the equation, why KMnO₄ is called an oxidising agent and not a catalyst, and one everyday connection.

Q170. Explain addition reactions fully through the hydrogenation of vegetable oils: the chemistry with equation form, the industrial process conditions, why the product is solid, the health perspective, and how the same reaction type serves as a laboratory test for unsaturation.

Q171. Compare all four reaction types of this topic in one organised answer — reactants, conditions, products, one equation each — and close with the rule connecting a compound's structure to its reaction menu.

Q172. Consider these statements about ethanol. I. It is a colourless liquid that mixes with water in all proportions. II. It has no effect on litmus. III. It reacts with sodium to give hydrogen. IV. It turns blue litmus red, since it contains an —OH group. Which statements are correct?

Q173. A small piece of sodium is dropped into ethanol and a gas bubbles off that burns with a pop. Which statement is correct?

Q174. Ethanol is heated with excess concentrated sulphuric acid at 443 K. The product and the role of the acid are:

Q175. Assertion (A): Concentrated sulphuric acid plays a different role in the dehydration of ethanol and in esterification. Reason (R): In the first it removes water from a single molecule, and in the second it acts as a catalyst that helps an acid and an alcohol join.

Q176. Which of these best explains why pure ethanoic acid is called GLACIAL acetic acid?

Q177. What is the best explanation of why ethanoic acid is called a WEAK acid while hydrochloric acid is called strong?

Q178. Which everyday observation shows that ethanoic acid is a weaker acid than hydrochloric acid?

Q179. Consider these reactions of ethanoic acid. I. With sodium carbonate it gives brisk effervescence of carbon dioxide. II. With sodium hydroxide it gives sodium ethanoate and water. III. With an alcohol and a little concentrated sulphuric acid it gives an ester. IV. With sodium metal it gives no reaction at all. Which statements are correct?

Q180. Which is the correct explanation of why esters are used in perfumes and flavouring essences?

Q181. Ethanoic acid is warmed with ethanol and a few drops of concentrated sulphuric acid. The product CH₃COOC₂H₅ is named:

Q182. Assertion (A): Saponification and esterification are two names for the same reaction. Reason (R): Esterification joins an acid and an alcohol to make an ester, while saponification splits an ester with alkali back into an alcohol and the salt of the acid.

Q183. Which statement best explains why a soap molecule can clean oily dirt that water alone cannot?

Q184. Which sequence correctly describes how soap removes an oily stain?

Q185. Assertion (A): Soap forms micelles in water but not in a solvent such as kerosene. Reason (R): A micelle forms because the hydrocarbon tails are strongly attracted to water, and kerosene drives them out.

Q186. Consider these statements about hard water. I. It contains dissolved salts of calcium and magnesium. II. Soap forms a white curdy scum in it. III. A great deal of soap is wasted before any lather appears. IV. Detergents fail in hard water for the same reason soap does. Which statements are correct?

Q187. A family finds that washing with soap in their borewell water leaves a white deposit on the clothes and very little lather. The deposit is:

Q188. Which of these best explains why detergents are used in shampoos and washing powders while soap still has its place?

Q189. Which pair of tests would distinguish ethanol from ethanoic acid most quickly?

Q190. Why is industrial ethanol DENATURED before it is sold?

Q191. What is the best explanation of why methanol is far more dangerous to drink than ethanol?

Q192. Which pair distinguishes ethanol from ethanoic acid instantly?

Q193. Assertion: Detergents can lather in hard water. Reason: Their calcium and magnesium salts are water-soluble.

Q194. Assertion: Soap solution in kerosene cleans clothes well. Reason: Micelles form best in oils.

Q195. The white curdy deposit after washing with soap in borewell water is:

Q196. Ethanol → ethanoic acid → ester: the two reagents needed in order are:

Q197. Case: A perfume factory's vat holds a carboxylic acid, an alcohol, and a few drops of concentrated H₂SO₄, warmed. The product line is:

Q198. Case: Grandmother's soap lathers at the village well (rainwater tank) but not in the city flat. The best explanation is:

Q199. Which sequence correctly describes soap cleansing?

Q200. Saponification and esterification are related as: